Rotary brushing tools are widely used in industry for cleaning, polishing, deburring, finishing, and burnishing metals and other materials. Rotary brushing tools having a one-piece integral hub structure are desirable because the structural rigidity of such tools will produce a finer surface finish and increase the life of the tool.
One way of making rotary brushing tools having a one-piece integral hub structure involves placing bundles of non-woven bristles in a fixture, pouring an epoxy or similar material to form the hub into a mold, and allowing the material to cure to form a finished hub. However, the curing characteristics of the material can change from batch to batch and even within the same batch given changes in environmental conditions such as temperature and humidity. These changes to the curing characteristics of the material cause the internal diameter of the hub to fluctuate and possibly be outside desired tolerances. If the internal diameter of the hub is too small, the hub will not fit on an arbor. If the internal diameter of the hub is too large, the brush will just spin idly on the arbor. Either way, when the internal diameter of the hub fails to meet desired tolerances, the brush is essentially useless.